Question

Explain what epigenetics is. Give examples of specific molecular mechanisms at play

Answer 1

EPIGENETICS CAN BE DEFINED AS THE STUDY OF PHENOMENA THAT CAUSE CHROMOSOME ASSOCIATED HERITABLE CHANGES TO GENE EXPRESSION THAT ARE NOT DEPEND ON CHANGES IN DNA SEQUENCE. OR IT CAN BE DEFINED AS THE STUDY OF CHANGES IN GENE EXPRESSION THAT ARE NOT ASSOCIATED WITH THE CHANGES IN THE DNA SEQUENCES . THE IDEA OF EPIGENTICS WERE FIRST GIVEN BY TWO SCIENTISTS CONRAD H WADDINGTON AND ERNST HADORN DURING 1940S . THE TERM EPIGENTICS WERE COINED BY CONRAD H WADDINGTON IN 1942.THE SPECIFIC PATTERN OF EPIGENETIC MODIFICATIONS PRESENT INA CELL DURING A GIVEN PERIOD OF TIME IS KNOWN AS EPIGENOME. DURING THE LIFE SPAN OF AN ORGANISM IT HAS ONE GENOME WHICH CAN BE MODIFIED AT DIFFERENT TIMES TO MAKE DIFFERENT EPIGENOMIC STATES.

LIKE THE GENOME EPIGENOME CAN BE TRANSMITTED TO THE DAUGHTER CELLS THROUGH MITOSIS.EPIGENOME CAN BE TRANSMITTED TO FUTURE GENERATIONS THROUGH MEOSIS. RESEARCHES HAS FOUND THAT EPIGENETICALLY MODIFIED ALTERATIONS TO GENOME ARE ASSOCIATED WITH DISEASES LIKE CANCER AND DIABETES. SO RESEARCHES ARE GOING ON TO DEVELOP DRUGS THAT CAN MODIFY DISEASE ASSOCIATED EPIGENTIC CHANGES IN CELLS.

THE THREE MAJOR EPIGENTIC MECHANISMS IN CELLS ARE :

1. REVERSIBLE MODIFICATION OF DNA BY ADDITION OR REMOVAL OF METHYL GROUPS.

2. REMODELLING OF CHROMATIN BY ADDING OR REMOVING CHEMICAL GROUPS TO HISTONE PROTEINS.

3.REGULATION OF GENE EXPRESSION BY NON CODING RNA MOLECULES.

THESE MECHANISMS ALTER THE GENE EXPRESSION WITHOUT CAUSING ANY CHANGE IN DNA SEQUENCE.